Optical sighting device



Aug. l1, 1 925.

L.. LENOUVEL` OPTICAL SIGHTING DEVICE Filed Jan, l1, 1922 2 Sheets-Sheet l Ein/0110060 Aug. 11, 1925. 1,549,579

Y L. LENOUVEL OPTICAL S IGHTING DEVICE Filed Jan. 11, 1922 2 Sheets-Sheet 2 1pz/cm1 Z 5611/0 zl/Ue D) lj s.

Patented Aug. 11, 1925.

` "UNITED, STATES PATENT oFFICE.

"LEON LENoUvEL, or ROUEN, FRANCE, AssIeNoa To comrAeNiE EEEIENNE mur- AIsE, or sUEEsNEs, SEINE, FRANCE, A coEPoawrIoN or Eamon OPTICAL SIGHTING DEV'JICI.`

I Application led January 11, 1922. Serial No. 528,522.

To aZZ whom, t mag/concern:

' movement, and is obliged to carr Be it known that I, LEON LENoUvEL, a citizen of the French Republic, residing at Rouen, France, 'have invented certain new and useful Improvements in Optical Sight-Y ing Devices, of which the following is a. specification.

As a general rule the known sighting devices comprise a fixed eyehole on, small size disposed very near the eyepiece and against which the observers eye must be placed in order to perceive the entire iield of the sighting device. This obligation constitutes a diiiiculty for the observer, especially where the apparatus is used by a pilot on board an aeroplane who is occupied -with observations of the ground with a sighting device, but who has not all the desired freedom of out his operations in a rapid manner an without ceasing to look after the other apparatus on board.

The present invention relates to an optical sighting device wherein such drawbacks areV 2,5 obviated, and it comprises to this eect an ocular ring of 'large size and situated at a considerable distance from the end lens of the device. The said sighting device is constituted by two optical combinations disposed in sequence, whereof each is formed of an objective and a iield lens; the last combination may also comprise mirrors, and the end field lens may be replaced by a concave mirror; the real image constituted by each objective if formed upon the field lens fol- .lowing the same. A sighting device of this f type will aford a straight image. The .ocular ring which constitutes the image, in the ocular iield lens, of the objective situated in front of the same, has a considerable size, and it gives rise with this iield lens to a veritable ocular cone wherein the eye may be displaced while continuing to perceive 4g. all points of the eld.

vThe range of position or the field of ,the

eye' may be still further increased by constituting a composite sighting device where# in a pluralityl o elementary sighting devices of the above' mentioned type are so com bined that the lenses shall have the axes thereofin parallel disposition, but that the geometrical axes of these elementary sighting devices, or lines passing through the optical centres of the different lenses ofleach device, shall be concurrent and that all the ceive, all points of the field.

said elementary sighting vdevices shall cooperate with a given ocular field lens.

Thefollowing description, together with the accompanying drawing, sets forth various forms of construction of a simple and a composite sighting device according to the mvention, wherein:

Fig. l is a diagrammatic view of a simple rectilinear sighting device, and Figs. 2, 3 and 3 are like views of simple sighting de-r vices of the reection type. Fig. 4 is a diagrammatic view of a sighting device of the Y.

composite type. Figs. 5 and 6 represent two arrangements of the elementary lenses of the second objective of the said sighting device. ig; is a section of Fig. 6 on the plane The sighting piece shown in Fig. 1 com-V prises an acliromatic objective 1 forming a real and inverted image 2 upon the iirst field lens 3. A. second lens 4 forms at 5 a real and rectiiied image of 2 upon a second field lens 6. Therst field lens 3 is so disposed as to form, on the rear side of the objective l, an image which covers the front face of l the objective 4. Thesecond field lens @is so disposed as to provide, of the rear side of the objective 4, a real image 7 of suiiciently large size and situated at a certain distance from the lens 6, which size and distance will be determined in each particular case accircle 7'. By placing the eye at any point in this region which has a considerable depth and section, the observer will per- If the sightin 'piece is to be providedv -with a reticule, t e latter may be disposed either at 2 or at ,5, in the plane of one of the vtwo real images which are formed in the apparatus. Y Should it be necessary to perceive the image of ain apparatus such for instance as a level, compass or the like at the same time' as the image observed in the sighting 'projecd at 2 or' 5.

Y the ground from' an aeroplane. The arrange- The sighting devices of' simple character which are shown in Figs. 2 and 3 are com' structed particularly for the observation of ment shown inV Fig. 2- comprises thesamc op? pilot when the latter-places his head inthe normal position, the device has Ydisposed would have been produced by the objective 4l the lens 6. 2d in the casing 18. i wherein the observers eye may be placed is .j

directed towards the position normally oc,- l

'- cupied biyi after the objective 4 two mirrors 10 and 11 in such manner thatvthe image which is successivel disposed at 5 and 5'.' upon le sighting device is contained The cone 8-9 which v,determines-the `field the pilots headl when in the position of g l ocular ring 7 shall be adjacent the yobservers head.v Thepilot is thus enabled without I moving his head to. perceive Vthe whole ex tent of the ground comprised in the'ield of the sighting device -below the aeroplane without entirely abandoning the surveillance of the otherapparatus on board. -B giving a suitable `posltion t the mirrors t e operatorl can'causeth'e second real image 5'( -to be formed u011 theA second mirror 11; in Vthis case the end'v iield lens 6 will be applied The combination the mirror 11 and the lens 6 may be relaced by thelens 6 alone whereof the plane ace is silvered or a lens of this kind with silvered plane face may as is well known be replaced b 'a concave mirror. This combination is s ownin a diagrammatic manner in Figs. 3v andk 3 comprising an lelevation and a lan view. Theirst objective- 1.,-the first 'fie d lens 3, and the second objective 4 are thesameas indicated in Figs. 1 and 9.

A mirror 10 inclined with reference'to the optical axisis disposed after the objective 4 and sends the beamupon a spherical mirror 12-or. a field -lens 'having a sllver v,plane face-which sends the same to an ocular-ring.

situated va 'acent -the pilots eye 13. In the y plan view ig. 3', the cross 14 represents the optical axisof the lenses 1, 3, 4; the main body of the aeroplane is shown at -1'5; the

direction of travel of the aeroplane is indi- A sighting 05 wherein the section of the iield for the eye device can be constructed ita sighting devices, f tical elements vas thesi hting device shown. 011 fie Y' in'Fig. 1.-` In order tos ortenthe apparatusV and-to send the image in the proper direction,.or inthe direction' of the eye of the still further increased by lenses 3*, 3, 3

'primary objectives 1, 1", le. The primary objectives 1", 1", 1, have their optical axes parallel to each other, and are disposed in a .common transverse plane. The same is true for the lenses 3*, 3b, 3, and the objectives 4,

The secondaryimages 5, 5, 5 formed by y the-various combinations are superposed on ght and in suchv manner that thef may be preserved. As to the secondary objectives 4, 4", 4, these should be at least in the tangent positionas shown inplan in Fig. 5-to obviate' any discontinuity in the field uxtaposling a plurality of elementary sig ting detheV optical cenperceived by .the eye which would result in y a defective sighting. It is also preferable, as shown in lan in Fig. 6 and in section on the line M- Fig. 7, to constitute the `profile of the lenses according to a regular hexagon either com letelyl (4, 4, 4) or partiall (4d .I 4g ,thereby affording a honey com assemblage which will obviate all discontinuity in the light beam. According to the sense'wherein it is desired to increase the field visible to the eye, the different elementary sighting devices will be disposed accordi'ng to radial planes ors concentric circumferences, in such number as will be de- .termined by 'the individual characteristics of each lens.

The ieldperceived by the eye will be increasedin the said composite sighting. device as compared with the simple form of sighting device, from the fact that the ocular ring is the image, formed through the end eld -lensl 6, of the last objective4", 4", 4"; inasmuch as this is composite it will have a much greater surface than the single objective 4 of the simple -form of vsi htin device. The optical field of the sightlng evice itself vissubfstantially the same as that of a simple sighting device, since the optical axes of the first objectives 1, .1", 1c are in parallel disposition.

What I claim is: j

1. A sighting device comprising in seguence from rear to'front an objective, a

eld lens in the focal plane of said objective, a second objective upon which is formed an image of the rear part of the rst objective through the first field lens, and an optical device upon which is formed an image of the field lens through the second objective and forming an enlar ed image of the rear artof the second o jective at a certain istance.

.2. Asight device comprising in sequence from' rear to front an objective, a ield lens in the focal plane of said objective, a second objective upon which is formed an image of the rear partof the first objective through the first field lens, a plane mirror, andan op:- tical device upon which is formed an image of the field lens through the second objective and forming an enlarged image of rear part of lsecond objective-at a certain distance.

3. A sighting device comprising in seuence from rear/to front an objective, a eld lens in the focal plane of saidobjective, a second obj ect-ive u-pon which is formed an image of the rear part of the first objective through the first eld lens, a plane mirror, and a concave mirror upon which is formed an image of the eld lens through the second objective and formin an enlarged image of the rear part of t e second objective at a certain distance.

In Witness whereof I have hereunto set my hand.

LEON LENOUVEL. 

